CVE-2019-19920: sa-exim 4.2.1 allows attackers to execute arbitrary code if they can write a .cf file or a rule

This month

HIGH 8.8WATCHLISTDOWNGRADEMITIGATEMITIGATE

CVE-2019-19920 is a high-severity flaw (CVSS 8.8) affecting sa-exim, ubuntu linux, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

sa-exim 4.2.1 allows attackers to execute arbitrary code if they can write a .cf file or a rule. This occurs because Greylisting.pm relies on eval (rather than direct parsing and/or use of the taint feature). This issue is similar to CVE-2018-11805.

Why this priority

High severity
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	3.2% (top 12%)
CISA exploited list	No
Weakness	CWE-78
Published	2019-12-22
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: canonical · debian · sa-exim project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-12-22 18:15 UTCPublished CVE record published
2026-06-17 02:27 UTCUpdated Record last modified

sa-exim project sa-exim DOWNGRADE

Affected: 4.2.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.2.1

1. Check installed version

apt-cache policy sa-exim || rpm -q sa-exim || sa-exim --version

2. No fixed release: DOWNGRADE to a release before 4.2.1 (Debian / Ubuntu)

apt-cache madison sa-exim sudo apt install sa-exim=<VERSION_BEFORE_4.2.1> sudo apt-mark hold sa-exim

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list sa-exim sudo dnf downgrade sa-exim-<VERSION_BEFORE_4.2.1> sudo dnf versionlock add sa-exim

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

canonical ubuntu linux MITIGATE

Affected: 16.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 16.04

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 8.0 · 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2019-19920?

sa-exim: downgrade or apply the listed mitigation; ubuntu linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-19920 being exploited?

CVE-2019-19920 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2019-19920 affect?

CVE-2019-19920 affects sa-exim, ubuntu linux, debian linux. Severity is high (CVSS 8.8). sa-exim 4.2.1 allows attackers to execute arbitrary code if they can write a .cf file or a rule. This occurs because Greylisting.pm relies on eval (rather than direct parsing and/or use of the taint feature). This issue is similar to CVE-20

How urgent is CVE-2019-19920?

Priority 58/100. High severity; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities · Exim vulnerabilities

References

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